Explosive fire alarm



Jan. 24, 1967 G. J. CARTIER EXPLOSIVE FIRE ALARM Filed Sept. 28, 1965 FIG...?

Inventor GERALD J. CARTIER 3,299,850 EXPLOSIVE FIRE ALARM Gerald J. Cartier, Barrie, Ontario, Canada, assignor to Gerald J. Cartier, Thomas H. Cartier, and Bernard J. Cartier, all of Barrie, Ontario, Canada Filed Sept. 28, 1965, Ser. No. 490,908 1 Claim. (Cl. 116-105) This invention relates to an audible alarm device and more particularly to a fire alarm device of the detonator or explosive type.

There has long been a need for an inexpensive and reliable fire alarm device designed primarily for usage in houses, hotels and the like. To accommodate this need several devices of the explosive type have been developed, all of which provide means for attaching the unit to the exposed surfaces of walls, ceilings and the like. The feasibility of such devices suffers from the inherent fear in potential users of having an unconfined explosive device in their presence. Further, the exposed devices are prone to the tamperings of children and the possible disastrous consequences which might arise therefrom. Additionally, the shrapnel which emanates upon detonation from an exposed device of this nature constitutes a hazard to anyone in close proximity thereto. Due to these disadvantages, the prior art explosive alarm devices have proved unacceptable and in consequence thereof the public has been denied a safe, reliable and inexpensive means for heralding impending disaster from fire.

Accordingly, it is the main object of the present invention to provide an inexpensive fire alarm device which will overcome the aforesaid disadvantages.

It is another object of this invention to provide an explosive alarm device adapted for concealment within a recess formed within the structure or furnishings of a building, thereby to obviate accidental detonation of the device and discourage tampering therewith.

It is yet another object of this invention to provide an explosive alarm device wherein danger from pieces of material thrown by the explosion is reduced to a minimum.

With the foregoing and other objects in view as will appear from a reading of the following specification and claim, the invention resides in the novel arrangement and combination of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention may be made within the scope of what is claimed without departing from the spirit of the invention. It will be further understood that the invention is susceptible of embodiment in many and various forms and that the structural details herein set forth may be varied to suit particular purposes and still remain within the inventive concept.

In the drawings:

FIGURE 1 is a view in perspective of the device of this invention as it would appear installed for use;

FIGURES 2 and 3 are sectional views of the device taken along lines 22 and 33 respectively of FIG- URE 1; and

FIGURE 4 is a sectional view illustrating the manner in which the device of the invention is housed within a structure.

Referring now to the drawings for a detailed description of the invention and wherein like numerals represent like parts, a heat sensitive explosive ingredient 11 is confined within a capsule 12 by means of an insert 13 maintained in upright closure position within the capsule in any known manner such as by crimpings 14 and 15 formed in portions of the capsule side wall 16 adjacent the insert. The explosive ingredient is thus confined in a United States Patent manner such that the detonation thereof is accompanied by an audible report sufliciently loud to attract the attention of anyone in relatively close proximity thereto. Although ordinary gun powder Will sufiice, ingredient 11 is preferably of the initiator explosive type used primarily for initiating the detonation of high explosives and characterized in that they do not burn but explode with considerable noise and shock upon being subjected to elevated temperatures or to percussion. These explosive ingredients are further characterized by their long shelf life. Examples of such initiators are mercury fulminate, lead .azide, lead picrate and diazodinitrophenal. It is contemplated that upon ingredient 11 reaching a predetermined temperature within the capsule, it will explode thereby blowing out insert 13 and emitting a loud report. As ingredient 11 is thermally detonated by virtue of heat transferred through the walls of capsule 12 from the surrounding atmosphere, it is desirable, in order to reduce the time lag between the atmosphere reaching a predetermined temperature and the detonation 0f ingredient 11 that capsule 12 be constructed from material of high thermal conductivity such as copper, brass or the like.

Blank cartridge shells suit this requirement and the different oalibres thereof lend to a size range of alarm devices adapted to accommodate most any need. As there is always some danger from pieces thrown by the detonation of the charge within the capsule, it is preferable that insert 13 be made of disintegrable material such that upon explosion of the device the insert will be reduced to small pieces. Plaster, paper, wax and wood are typical examples of materials from which the insert could be made.

It is intended that the device of the instant invention be secured within recesses formed in the walls, ceiling, floor or furnishings of a room such that it will be unexposed and free from accidental detonation and unauthorized tamperings. The said recesses open into the room and the alarm devices are positioned, with the end thereof containing the insert, adjacent the inlet to the recess in order that the noise and shock of the explosion will be directed into the room. In order to achieve optimum reliability and efiiciency of operation, the device must fit loosely within the confines of the recess so that there will be adequate space for the convection of air around the capsule. Additionally, the said space will tend to obviate undue mufiling of the explosion by the material defining the recess.

To permit positioning of the device within the recess as aforesaid and to obstruct easy removal therefrom, capsule 12 is provided with a sleeve 17 having a plurality of slits therein. A flange 19 prevents the removal of sleeve 17 over the end 20 of the capsule. Upon installation of the alarm device, the arms 21 defined by the material between edges 18 and 18a are bent permanently out of the plane of sleeve 17 as illustrated in FIGURE 1 to present an overall cross-section slightly larger than the Width of the recess. It will thus be seen that as capsule 12 is pushed into a recess 22 with the insert end thereof adjacent the mouth of the recess, arms 21 will deflect inwardly toward the capsule. Accordingly, the capsule is secured within the recess by the tensioned contact of arms 21 against the walls thereof. An attempt to pull the capsule from the recess will simply cause the arms 21 to bend further thus frustrating unauthorized or mischievous removal of the device.

In practice a number of alarm devices are positioned as illustrated in FIGURE 4 in recesses strategically located about a building, as for example in walls adjacent curtain material, adjacent chimneys and heating elements, in mattresses and sofas and in other articles of household or ofiice furnishings. Should a fire ignite in the vicinity of the device, the heat therefrom will detonate the ex- 3 plosive charge within the capsule and thus warn of impending danger. l i i i From the foregoing description, it will be seen that the device of the present invention comprises a heat sensitive audible fire alarm adapted for concealment within a recess strategically located in the structure or furnishings of a building and comprising a capsule member; a heat sensitive explosive charge within said capsule; a capsule insert for closing an end of said capsule and confining said charge therewithin, and means associated with said capsule member for impinging upon a wall of said recess thereby to secure said device wit-hin'said recess and obstruct unauthorized removal and tampering therewith.

The foregoing is a description of a preferred embodiment of the invention and is hereby made by Way of example only. It is not intended to thereby limit the scope of the invention to any of the specific steps described and the invention comprehends all such variations as come within the spirit and scope of the appended claim.

What I claim is:

A heat sensitive audible fire alarm device of predetermined siz/e adapted for concealment with an oversize recess having cylindrical walls strategically located in the structure, furnishings and the like of a building and comprising: a cylindrical heat conductive capsule member of predetermined length and diameter and having a sealed end and an open end; a heat sensitive explosive charge within" said capsule; a capsule insert closing said open end of said self-destructive capsule and confining said charge therewithin; said insert formed of disintegrating material and being secured in closure position within said capsule by deforming inwardly portions of the capsule adjacent said insert; a cylindrical sleeve member fitting around and fastened to the exterior of said capsule member, at least two spring arm members fonrned integrally with said .sleeve member and angularly projecting away from said capsule member toward said open end thereof containing said insert for engagement with a wall of said recess, said sleeve and arm members being ofreduced length in comparison with the length of said capsule member and said arm members being dimensioned and oriented to resiliently engage the cylindrical walls of said recess, and a sleeve abutting flange on said capsule member adjacent said sealed end to prevent withdrawal of said sleeve from said capsule.

References Cited by the Examiner UNITED STATES PATENTS 1,602,963 10/1926 Brooks 116-405 1,617,794 2/ 1927 DAgostino 220- LOUIS J. CA'POZI, Primary Examiner. 

